1. Field of the Invention
The present invention relates to a process for producing novel pyrazolo[1,5-b][1,2,4]triazole derivatives.
2. Description of the Prior Art
A 5-5 condensed polycyclic compound represented by general formula (I) depicted below is named "azapentalene" ##STR1## wherein, broken lines (-- -- -- --) indicate three double bonds that shift from one position to another,
dots (.cndot.), located at the apices, each indicate a nitrogen atom or carbon atom.
In addition to the nitrogen atom at the bridgehead position, the compound has at least one more nitrogen atom and therefore it has 2 to 6 nitrogen atoms in total, and the interaction of 10 .pi.-electrons (including the lone pair of electrons in the nitrogen atom at the bridgehead position and those in other nitrogen atom(s) if present is possible in the molecule. This compound aroused researchers' interest from viewpoints of structural chemistry, physiological activity and applications as a photographic magenta coupler. (See J. Elgureo, R. Jacquier, S. Mignonac-Mondon, J. Heterocyclic. Chem., 10, 411 (1973); H. Koga, M. Hirobe, T. Okamoto, Chem. Pharm. Bull., 22, 482 (1974); J. Bailey, J. C. S. Perkin I 2047 (1977); Japanese Patent Publication No. 27411/1972; and Japanese Patent Laid-open No. 129586/1975.)
However, the conventional azapentalene compound a pyrazolo[5,1-c][1,2,4]triazole as a photographic magenta coupler are not necessarily satisfactory in hue and fastness to light and heat.
In order to develop a new coupler compound which is free of the disadvantages of the conventional azapentalene compound, the present inventors carried out a series of researches which have led to the finding that an azapentalene compound having a new skeleton is synthesized by ring closure of an amidoxime compound having a pyrazolyl group and that this azapentalene compound is satisfactory to achieve the above-mentioned objective. This compound is a pyrazolo[1,5-b][1,2,4]triazole derivative, which is disclosed in the copending continuation-in-part of application Ser. No. 702,691, Ser. No. 590,818, now U.S. Pat. No. 4,540,654.